The objectives of this research are (a) to study the biochemical action of hypocholesteremic drugs which inhibit the growth of Tetrahymena pyriformis and/or Saccharomyces cerevisiae, (b) to distinguish between primary and secondary effects of the drugs on metabolism, and (c) to seek clarification of unexpected biochemical phenomena that may be observed during these studies. Scientific objectives are: (1) to isolate and characterize unidentified lipids whose rate of synthesis is modified by hypocholestermic compounds. (2) To study the effects of 3 beta (beta- dimethylaminoethoxy)-androst-5-en-17-one and related compounds on (a) P32-inorganic phosphate incorporation into cellular components, (b) mitochondrial function, and (c) in vitro protein synthesis. (3) To investigate effects of other hypocholesteremic compounds on growth and metabolic processes in T. pyriformis and in S. cerevisiae. (4) To purify a squalene cyclase activator protein. (5) To study the mechanism of biosynthesis of fatty acid esters of ethanol. (6) To determine the distribution of tetrahymanol in cell organelles of T. pyriformis. Conventional procedures for purification of proteins and lipids will be used as required.